- A novel one-pot conversion of 2-naphthols into 1,1′-binaphthalene-2,2′-diols
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A simple two-step, one-pot procedure based on the treatment of sodium 2-naphthoxide with bromine yields 1,1′-binaphthalene-2,2′-diol in a high yield and an excellent purity. The procedure is applicable also to preparation of the symmetrically disubstituted analogues.
- Holy, Petr,Belohradsky, Martin,Zavada, Jiri
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- A Dearomatization/Debromination Strategy for the [4+1] Spiroannulation of Bromophenols with α,β-Unsaturated Imines
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A novel [4+1] spiroannulation of o- & p-bromophenols with α,β-unsaturated imines has been developed for the direct synthesis of a new family of azaspirocyclic molecules. Notably, several other halophenols (X=Cl, I) were also applicable for this transformation. Moreover, a catalytic asymmetric version of the reaction was realized with 1-bromo-2-naphthols by using a chiral ScIII/Py-Box catalyst. Mechanistic studies revealed that this domino reaction proceeded through electrophile-triggered dearomatization of phenol derivatives at their halogenated positions and followed by halogen-displacement with N-nucleophiles via a radical-based SRN1 mechanism.
- Bai, Lu,Ge, Yicong,Hao, Jiamao,Liu, Jingjing,Luan, Xinjun,Qin, Cheng
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supporting information
p. 18985 - 18989
(2020/08/26)
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- Iodine(III)-Mediated, Controlled Di- or Monoiodination of Phenols
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An oxidative procedure for the electrophilic iodination of phenols was developed by using iodosylbenzene as a nontoxic iodine(III)-based oxidant and ammonium iodide as a cheap iodine atom source. A totally controlled monoiodination was achieved by buffering the reaction medium with K3PO4. This protocol proceeds with short reaction times, at mild temperatures, in an open flask, and generally with high yields. Gram-scale reactions, as well as the scope of this protocol, were explored with electron-rich and electron-poor phenols as well as heterocycles. Quantum chemistry calculations revealed PhII(OH)·NH3 to be the most plausible iodinating active species as a reactive "I+" synthon. In light of the relevance of the iodoarene moiety, we present herein a practical, efficient, and simple procedure with a broad functional group scope that allows access to the iodoarene core unit.
- Satkar, Yuvraj,Yera-Ledesma, Luisa F.,Mali, Narendra,Patil, Dipak,Segura-Quezada, Luis A.,Ramírez-Morales, Perla I.,Solorio-Alvarado, César R.,Navarro-Santos, Pedro
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p. 4149 - 4164
(2019/04/30)
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- Practical, mild and efficient electrophilic bromination of phenols by a new I(iii)-based reagent: The PIDA-AlBr3 system
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A practical electrophilic bromination procedure for phenols and phenol-ethers was developed under efficient and very mild reaction conditions. A broad scope of arenes was investigated, including the benzimidazole and carbazole core as well as analgesics such as naproxen and paracetamol. The new I(iii)-based brominating reagent PhIOAcBr is operationally easy to prepare by mixing PIDA and AlBr3. Our DFT calculations suggest that this is likely the brominating active species, which is prepared in situ or isolated after centrifugation. Its stability at 4 °C after preparation was confirmed over a period of one month and no significant loss of its reactivity was observed. Additionally, the gram-scale bromination of 2-naphthol proceeds with excellent yields. Even for sterically hindered substrates, a moderately good reactivity is observed.
- Satkar, Yuvraj,Ramadoss, Velayudham,Nahide, Pradip D.,García-Medina, Ernesto,Juárez-Ornelas, Kevin A.,Alonso-Castro, Angel J.,Chávez-Rivera, Ruben,Jiménez-Halla, J. Oscar C.,Solorio-Alvarado, César R.
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p. 17806 - 17812
(2018/05/28)
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- Synthesis of 2-arylbenzofuran-3-carbaldehydes: via an organocatalytic [3+2] annulation/oxidative aromatization reaction
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A novel organocatalytic [3+2] annulation/oxidative aromatization reaction of enals with 2-halophenols or β-naphthols is reported. This process enables chemo- and regioselective access to 2-arylbenzofuran-3-carbaldehydes without the use of transition metals or strong oxidants. Preliminary mechanistic studies reveal that an unprecedented, organocatalytic, direct α-arylation pathway is involved.
- Zhang, Huiwen,Ma, Chunmei,Zheng, Ziwei,Sun, Rengwei,Yu, Xinhong,Zhao, Jianhong
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supporting information
p. 4935 - 4938
(2018/05/23)
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- Process for synthesizing 6-bromo-2-naphthol
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The invention relates to a process for synthesizing 6-bromo-2-naphthol. The process comprises the following steps: (S1) mixing 2-naphthol and a bromo salt, and adding the mixture into a reactor; (S2) adding an acetic solution into the reactor in the step (S1); (S3) dropwise adding an oxidant into the reactor while carrying out stirring, and carrying out a heat-insulating reaction after dropwise adding is completed, so as to obtain an intermediate solution; (S4) heating the temperature of the reactor to a definite value, adding nano Pd/Fe into the intermediate solution obtained in the step (S3), introducing nitrogen gas into the reactor, and carrying out a reaction while controlling the temperature and pressure to definite values; (S5) cooling the reactor, adding pure water into the reactor in the step (S4) for dilution, and carrying out standing for a period of time for crystallization; and (S6) subjecting the crystals obtained in the step (S5) to filtering and washing, adding the crystals into an acetic solution for recrystallization, and subjecting the recrystallized crystals to filtering, washing and drying, thereby obtaining a finished product. According to the process, on one hand, the utilization ratio of atoms is increased, and large-area pollution to environments caused by reactions is prevented; and on the other hand, the requirements of a reaction process on public works are relatively low, the reaction rate is relatively high, and the purity and yield of the obtained final product are relatively high, so that the process is applicable to industrial mass production.
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Paragraph 0035
(2017/05/23)
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- Lead optimization of 17β-HSD1 inhibitors of the (hydroxyphenyl) naphthol sulfonamide type for the treatment of endometriosis
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The reduction of estrone to estradiol, the most potent estrogen in human, is catalyzed by 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1). A promising approach for the treatment of estrogen-dependent diseases is the reduction of intracellular estradiol formation by inhibition of 17β-HSD1. For the species-specific optimization of the (hydroxyphenyl)naphthols, a combinatorial approach was applied and enhanced by a focused synthesis that resulted in the aromatic-substituted (hydroxyphenyl)naphthol sulfonamides. Rigidification of 12 led to the 4-indolylsulfonamide 30, which is a highly active and selective human 17β-HSD1 inhibitor, as well as a highly potent and selective inhibitor of 17β-HSD1 from Callithrix jacchus. It shows no affinity to the estrogen receptors I?± and β and good intracellular activity (T47D). Thus, compound 30 shows good properties for further ADMET studies and might be a candidate for the in vivo proof of concept in C. jacchus.
- Henn, Claudia,Einspanier, Almuth,Marchais-Oberwinkler, Sandrine,Frotscher, Martin,Hartmann, Rolf W.
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supporting information; experimental part
p. 3307 - 3318
(2012/06/01)
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- An instant and facile bromination of industrially-important aromatic compounds in water using recyclable CaBr2-Br2 system
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Various industrially-important brominated intermediates have been instantly synthesized using aq. CaBr2-Br2 system as an efficient and recyclable brominating reagent under aqueous conditions at room temperature without the need for metal catalysts or acidic additives. Structurally-diverse phenol and aniline derivatives with strong electron-withdrawing groups such as carboxylic, nitro and formyl show remarkable reactivity to the brominating reagent and brominated in 92-98% yield with high purity (>99%) in a very short reaction time. Organic solvent-free conditions, a feature of the green chemistry, were successively used not only for the reactions but also for the isolation of products at the end of the reaction. The recycling of HBr by its neutralization, thereby generating additional amounts of industrially-important CaBr2 has been designed and developed. The brominating reagent has been recycled and regenerated, and the process was repeated up to 4 cycles after the fresh batch using the regenerated brominating reagent having almost identical selectivity and isolated yields, which seems to be the most promising methodology from the viewpoint of the green approach to organic synthesis.
- Kumar, Lalit,Mahajan, Tanu,Agarwal
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experimental part
p. 2187 - 2196
(2011/09/16)
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- 17BETA-HYDROXYSTEROID DEHYDROGENASE TYPE 1 INHIBITORS FOR THE TREATMENT OF HORMONE-RELATED DISEASES
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The invention relates to the use of non-steroidal 17beta-hydroxysteroid dehydrogenase type 1 inhibitors for the treatment and prophylaxis of hormone-dependent, particularly estrogen-dependent, diseases.The invention further relates to suitable inhibitors and to a method for the production thereof.
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Page/Page column 15
(2010/08/18)
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- Environmentally benign chlorination and bromination of aromatic amines, hydrocarbons and naphthols
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A simple and efficient procedure for chlorination and bromination of aromatic amines, hydrocarbons and naphthols by the action of aqueous hydrohalic acid and hydrogen peroxide is described. This environmentally clean and safe procedure involves in situ generation of the active halogen and its uncatalyzed reaction with the substrates in this study.
- Vyas, Punita V.,Bhatt, Anjani K.,Ramachandraiah, Gadde,Bedekar, Ashutosh V.
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p. 4085 - 4088
(2007/10/03)
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- Process research and structural studies on nabumetone
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A short, simple and economical process for large-scale preparation of nabumetone has been developed. The single-crystal structures of nabumetone and one of its key intermediates have been determined by X-ray diffraction studies. Two impurities have been isolated and characterised.
- Prabhakar,Reddy, C. Bakki,Reddy, Ch. Maheedhara,Nageshwar,Devi, A. Sivalakshmi,Babu, J. Moses,Vyas,Sarma,Reddy
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p. 121 - 125
(2013/09/08)
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- Production of racemic 2-(6-methoxy-2-naphthyl) propionic acid of precursors thereof
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In producing (±)-2-(6-methoxy-2-naphthyl)propionic acid or precursor thereof from 2-bromo-6-methoxynaphthalene, use is made of 2-bromo-6-methoxynaphthalene formed by (a) methylating 6-bromo-2-naphthol with methyl chloride in a solvent comprising one or more compounds, RZ, where R is a hydrogen atom or an alkyl group, and Z is --OH or --CN provided that if Z is --CN, R is alkyl, and in the presence of a strong base; and (b) recovering and purifying 2-bromo-6-methoxynaphthalene so formed. Preferably, the 6-bromo-2-naphthol is formed by (1) reacting 1,6-dibromo-2-naphthol with hydrogen, in a solvent comprising (a) organic halide in which the halogen has an atomic number of 35 or less or (b) a mixture of water and such organic halide, and in the presence of catalytically effective amounts of (i) a tungsten carbide-based catalyst, and (ii) phase transfer catalyst; and (2) separating 6-bromo-2-naphthol from the organic halide solvent so that the 6-bromo-2-naphthol is substantially free of halogen-containing impurities before use in the above methylation reaction. This technology makes possible reductions in quantities of co-products formed, eliminates need for use of excess iron and/or dimethyl sulfate as reaction components, and makes possible improvements in plant operating efficiency. Precursors of (±)-2-(6-methoxy-2-naphthyl)propionic acid formed from such 2-bromo-6-methoxynaphthalene are Grignard reagent of 2-bromo-6-methoxynaphthalene, bis(6-methoxy-2-naphthyl)zinc, 6-methoxy-2-naphthylzinc halide, 6-methoxy-2-naphthyllithium, 6-methoxy-2-naphthylcopper(I), bis(6-methoxy-2-naphthyl)cadmium, 6-methoxy-2-naphthylcadmium halide, and 6-methoxy-2-vinylnaphthalene.
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